The architecture of a base station mainly includes a base band signal processing unit, a radio-frequency (RF) unit, a master transmission clock, a power supply, a fan and some peripheral circuits. FIG. 1A is a schematic diagram of the architecture of a base station in the conventional art. As shown in FIG. 1A, except for the radio-frequency units, the other parts may be physically integrated into a Base Band Unit (BBU). The radio-frequency unit may either be installed together with the base band unit in a cabinet, or may be a Remote Radio Unit (RRU) remotely connected via a medium such as a cable or optical fiber. FIG. 1B is a schematic diagram of a distributed base station architecture in prior art. As shown in FIG. 1B, the BBU here may be connected with an RRU via a Common Public Radio Interface (CPRI).
The RF unit mainly includes a digital intermediate frequency module, an analog-to-digital/digital-to-analog (AD/DA) conversion module, a radio-frequency transceiving channel, a power amplification module, a duplexer, a power supply, etc. The up-conversion technology is employed in a downlink transmitting channel of the RF unit to modulate signals to an RF transmitting band, where the signals are filtered, amplified or combined, and then sent by a duplex filter to an antenna for transmission to a wireless terminal. In an uplink receiving channel, RF signals are received via an antenna, and the received signals are down-converted to intermediate frequency signals, which then undergo amplification, analog-to-digital conversion, digital down-conversion, matching and filtering, and Automatic Gain Control (AGC), and are sent via an interface (e.g., a CPRI interface if the RF unit is an RRU) to the BBU for processing.
The BBU mainly performs base band signal processing, where the signal processing includes modulation, demodulation, L2/L3 control, transmission, operation maintenance, etc. The BBU is connected with a transmission network via a transmission interface, e.g., E1/T1, Ethernet interface, and is connected with a base station controller, a core network, or other network elements.
To improve reliability, at least two assembled RF units are usually employed for a single sector in the conventional art. FIG. 2 illustrates a schematic diagram where two assembled RF units are used for a single sector to improve reliability. In this way, if any one of the RF units of the sector fails, it may only result in the decrease of capacity and performance of the sector rather than the interrupt of service.
In implementing the present invention, it is discovered that the solution of the conventional art encounters the problem of high cost since at least one extra RF unit is required.